Benjamin Geffroy

Benjamin Geffroy
Institut Français de Recherche pour l'Exploitation de la Mer | Ifremer · Department of Environment and Resources

PhD Reproduction physiology & Behavioural Ecology

About

60
Publications
39,059
Reads
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1,211
Citations
Citations since 2017
41 Research Items
1052 Citations
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Introduction
I'm working on various topics in Evolutionary Biology and Ecology at the French Institute for the Exploitation of the Sea (IFREMER). My three main axis are 1) The effect of stress on sex determination in fish, from physiology to ecological consequences 2) The effect of human presence on fish stress and reproduction and 3) Understanding causes and consequences on animal variations in behaviour.
Additional affiliations
July 2015 - November 2016
French National Institute for Agriculture, Food, and Environment (INRAE)
Position
  • PostDoc Position
Description
  • Fish stress regulation
August 2013 - June 2015
State University of Mato Grosso
Position
  • PostDoc Position
October 2009 - December 2012
French National Institute for Agriculture, Food, and Environment (INRAE)
Position
  • PhD Student

Publications

Publications (60)
Article
The impact of early stress on juvenile development has intrigued scientists for decades, but the adaptive significance of such effects remains an ongoing debate. This debate has largely ignored some characteristics of the offspring, such as their sex, despite strong evolutionary and demographic implications of sex-ratio variation. We review recent...
Article
Full-text available
In an increasingly anthropic world, humans have profound impacts on the distribution and behaviour of marine fishes. The increased human presence has modified fishes’ antipredator behavioural responses, and consequently flight decisions, as a function of their changed perceptions of risk. Understanding how fish react to human presence can help iden...
Article
Full-text available
In fishes, sex is either determined by genetics, the environment, or an interaction of both. Temperature is among the most important environmental factors that can affect sex determination. As a consequence, changes in temperature at critical developmental stages can induce biases in primary sex ratios in some species. However, early sex ratios can...
Article
Full-text available
Humans profoundly impact landscapes, ecosystems, and animal behavior. In many cases, animals living near humans become tolerant of them and reduce antipredator responses. Yet, we still lack an understanding of the underlying evolutionary dynamics behind these shifts in traits that affect animal survival. Here, we used a phylogenetic meta-analysis t...
Article
Significance Traditionally, fish sex determination was considered to be governed by genetic or environmental factors. However, many teleost species defy this dichotomy. We combined genomic and transcriptomic approaches to characterize the temperature-dependent polygenic sex determination of European sea bass. We observed that the estimated genetic...
Article
Rapid environmental changes will be the major challenge that most biota will have to deal with in the near future. Extreme events, such as marine heatwaves, are becoming more frequent and could be spatially uniform at a regional scale for a relatively long period of time. To date, most research on heatwaves have focused on sessile organisms, but th...
Article
Full-text available
Converging lines of inquiry from across the social and biological sciences target the adult sex ratio (ASR; the proportion of males in the adult population) as a fundamental population-level determinant of behavior. The ASR, which indicates the relative number of potential mates to competitors in a population, frames the selective arena for competi...
Article
In recent years, observations of distinct organisms have linked the quality of the environment experienced by a given individual and the sex it will develop. In most described cases, facing relatively harsh conditions resulted in masculinization, while thriving in favorable conditions promoted the development of an ovary. This was shown indistincti...
Article
Full-text available
In this study, we aimed to investigate the relationship between cortisol and the determination of sexual fate in the commercially important European sea bass (Dicentrarchus labrax). To test our hypothesis, we designed two temperature-based experiments (19 ℃, 21 ℃ and 23 ℃, experiment 1; 16 ℃ and 21 ℃, experiment 2) to assess the effects of these th...
Article
Bolder individuals have greater access to food sources and reproductive partners but are also at increased risk of predation. Boldness is believed to be consistent across time and contexts, but few studies have investigated the stability of this trait across variable environments, such as varying stress loads or long periods of time. Moreover, the...
Conference Paper
Full-text available
Les rayonnements ionisants induisent des effets délétères chez les organismes, notamment au fil des générations. En effet, une étude précédente a montré une altération du sexe ratio (1 femelle pour 4 mâles) chez la descendance de poisson zèbre après irradiation des parents. Un tel effet pourrait s'avérer drastique pour le devenir des populations. A...
Presentation
Full-text available
Les rayonnements ionisants induisent des effets délétères chez les organismes, notamment au fil des générations. En effet, une étude précédente a montré une altération du sexe ratio (1 femelle pour 4 mâles) chez la descendance de poisson zèbre après irradiation des parents. Un tel effet pourrait s'avérer drastique pour le devenir des populations. A...
Article
Mass reproduction is widely used in fish farms because it is relatively easy and inexpensive. It also enables the development of mass selection programmes that provide gains for traits with high heritability. The main weakness of this approach is that it is currently impossible to know which females participated in reproductive events, unless by co...
Article
Social rank in a structured society has been linked to basal levels of glucocorticoids in various species, with dominant individuals generally presenting lower levels than subordinates. The biotic and abiotic factors influencing glucocorticoids levels across social ranks are still, however, unclear in fishes. We investigated the influences of group...
Article
Full-text available
In European sea bass (Dicentrarchus labrax), as in many other fish species, temperature is known to influence the sex of individuals, with more males produced at relatively high temperatures. It is however unclear to what extent growth or stress are involved in such a process, since temperature is known to influence both growth rate and cortisol pr...
Article
Cortisol is recognized as a physiological indicator of stress in fish. However, this hormone is typically measured in plasma samples. In this study, cortisol content was evaluated for the first time in the scales of tropical tuna. The sample included 20 skipjack tuna (Katsuwonus pelamis) and 25 yellowfin tuna (Thunnus albacares) collected in the At...
Article
Full-text available
Wild animals face novel environmental threats from human activities that may occur along a gradient of interactions with humans. Recent work has shown that merely living close to humans has major implications for a variety of antipredator traits and physiological responses. Here, we hypothesize that when human presence protects prey from their genu...
Article
Full-text available
The mutable nassa, Tritia mutabilis, a marine gastropod that is widely exploited on the Adriatic coast is an important source of income for small-scale fishermen in the Mediterranean Sea, particularly in the Gulf of Lion. However, the lack of knowledge on the ecology and biology of this species limits our capacities to propose and produce an effect...
Article
Sex allocation research has primarily focused on offspring sex-ratio adjustment by mothers. Yet, fathers also benefit from producing more of the sex with greater fitness returns. Here, we review the state-of-the art in the study of male-driven sex allocation and, counter to the current paradigm, we propose thatmales can adaptively influence offspri...
Article
Full-text available
Humans currently occupy all continents and by doing so, modify the environment and create novel threats to many species; a phenomenon known as human-induced rapid environmental changes (HIREC). These growing anthropogenic disturbances represent major and relatively new environmental challenges for many animals, and invariably alter selection on tra...
Article
Full-text available
Temperature‐dependent sex determination (TSD) can be observed in multiple reptile and fish species. It is adaptive when varying environmental conditions advantage either males or females. A good knowledge of the thermosensitive period is key to understand how environmental changes may lead to changes in population sex ratio. Here, by manipulating t...
Article
Hyperallometric reproduction, whereby large females contribute relatively more to the renewal of the population than small females, is purported to be widespread in wild populations, especially in fish species. Bioenergetic models derived from a sufficiently general metabolic theory should be able to capture such a relationship but it was recently...
Article
Full-text available
Changes in ocean water temperature associated with global climate change are bound to enormously affect fish populations, with potential major economic consequences in the aquaculture and fisheries industries. A link between temperature fluctuations and changes in fish stress response is well established. In this study, we aimed to assess the effec...
Article
In a recent paper, Dahlke et al. 2020 (1) highlighted how crucial it is to consider the different stages of the life cycle to accurately model how fish respond to global warming. While we agree with this view, we argue that predictive population dynamic models should also consider an overlooked characteristic of many fishes: their sex determination...
Article
Coping styles consist of a coherent set of individual physiological and behavioral differences in stress responses that are consistent across time and context. Such consistent inter-individual differences in behavior have already been shown in European sea bass (Dicentrarchus labrax), but the associated mechanisms are still poorly understood. Here,...
Article
Stress in teleosts is an increasingly studied topic because of its interaction with growth, reproduction, immune system and ultimately fitness of the animal. Whether it is for evaluating welfare in aquaculture, adaptive capacities in fish ecology, or to investigate effects of human‐induced rapid environmental change, new experimental methods to des...
Article
Stress enhances or inhibits neurogenesis in mammals and some fish species. The link between the two processes is still unclear. Most studies have been performed in very specific stressful or altered environments. Despite the known inter-individual divergence in coping abilities within populations, the relationship between the stress axis and neurog...
Article
Clear evidence for a physiological role of the mineralocorticoid-like hormone 11-deoxycorticosterone (DOC) and the mineralocorticoid receptor (MR) in fish is still lacking. Efforts to demonstrate an osmoregulatory role for this hormone has so far not been conclusive, while a few scattered studies have indicated a role for DOC in development and rep...
Article
Alien species are threatening native fauna worldwide and cats and dogs have well-documented deleterious impacts on wildlife. Ecotourism operators often live and raise their pets in natural reserves. Here we discuss how pets add to the list of potential negative impacts of ecotourism and provide recommendations to control or attenuate such impacts.
Article
Full-text available
Nature-based tourism is gaining extensive popularity, increasing the intensity and frequency of human-wildlife contacts. As a consequence, behavioral and physiological alterations were observed in most exposed animals. However, while the majority of these studies investigated the effects of punctual exposure to tourists, the consequences of constan...
Chapter
Full-text available
The goal of this book is to empower operators, regulators, and tourists to find the critical balance between possibly damaging consequences of wildlife tourism and the potential benefits to the local human communities, ecosystems, and the wildlife themselves. It is essential to realize that ecotourism is frequently more environmentally friendly tha...
Chapter
Full-text available
The more people lose contact with nature in their daily lives, the greater the need to compensate for this loss through nature-based recreation and ecotourism. However, these tourist activities are often not without consequences for animals. The mere presence of humans can affect resident wildlife. Short-term changes in physiology and behavior may...
Book
Intended as a guide for wildlife managers and ecotourism operators, as well as interested ecotourists, this book addresses the biological principles governing how ecotourism affects wildlife. The introductory chapters focus on four key responses to human visitation—behavioral, physiological, ecological, and evolutionary. Readers will discover ecoto...
Article
As nature-based tourism grows, its impacts on aquatic ecosystems follow, requiring effective management techniques to conserve river integrity. Nevertheless, strong indicators of tourism impacts are scarce and have seldom been studied for many species. This study evaluated whether microhabitat use and activity period of a variety of fish species ar...
Article
Full-text available
In the last decades animal production has considerably increased worldwide to sustain an ever-growing human population. Among animal reared for consumption purposes, chickens are undoubtedly one of the most successful, mainly due to their rapid growth rate. The development of broiler farming has been accompanied in recent years by a substantial att...
Chapter
Reducing ecotourism’s impacts on wildlife requires an evidence-based research agenda that recognizes both the magnitude and effect of anthropogenic stressors on wildlife while also recognizing the value of ecotourism to local communities. We suggest that operators and ecotourists themselves can play a vital role in collecting evidence that can be u...
Chapter
This is a book that desires to improve the positive impacts of ecotourism and nature-based tourism by properly identifying potential biological impacts so as to help develop effective mitigations and management. We focus mostly on impacts on wildlife. We bring a unique animal-behavior centered approach to potential impacts of eco- and nature-based...
Chapter
Clownfish represent one of the best examples of captive bred ornamental fish. This chapter not only considers the general biology and characteristics of this fish group, but also deals with important aspects related to their reproductive biology and rearing techniques. Details on tank design, spawning, broodstock and larval nutrition, larval rearin...
Article
Full-text available
Environmental sex determination (ESD) has been detected in a range of vertebrate reptile and fish species. Eels are characterized by an ESD that occurs relatively late, since sex cannot be histologically determined before individuals reach 28 cm. Because several eel species are at risk of extinction, assessing sex at the earliest stage is a crucial...
Article
Kleptoparasitism refers to either interspecific or intraspecific stealing of food already procured by other species or individuals. Within a given species, individuals might differ in their propensity to use such a tactic, in a similar manner to which they differ in their general level of aggressiveness. Standard metabolic rate is often viewed as a...
Article
We investigated the effects of an early boost of cortisol exposure in rainbow trout (Oncorhynchus mykiss) eggs during fertilisation on subsequent behavioural responses when exposed to a sudden stimulus in larvae and juveniles. At 55 d post-fertilisation (dpf), treatment had no effect on high accelerations occurring after a sudden event. At 146 dpf,...
Article
In a recent review [1] we developed a framework to identify potential ecological consequences of long-term benign interactions between humans and animals and to highlight potential deleterious effects of non-threatening wildlife viewing by tourists. Fitzgerald and Stronza [2] questioned our hypothesis stating that ‘It sends a countervailing, mixed...
Article
Tourism can be deleterious for wildlife because it triggers behavioral changes in individuals with cascading effects on populations and communities. Among these behavioral changes, animals around humans often reduce their fearfulness and antipredator responses towards humans. A straightforward prediction is that habituation to humans associated wit...
Research
Full-text available
Le plan de gestion anguille prévoit qu’une partie des civelles pêchées soit dédiée à des opérations de repeuplement (qui consistent en des transferts d’individus pêchés). Par ailleurs, il prévoit aussi de mettre en place les outils et les suivis permettant d’apprécier la production de géniteurs par bassin et leur qualité. Ce travail permet d’appor...
Article
The aim of this review is to present an overview of the sex differentiation and sex determination processes in eels in relation to the urgent need to provide scientific knowledge to better protect and manage the Anguilla genus. Indeed, the global decline of the three main temperate eel stocks, Anguilla anguilla, Anguillidae (Fisheries Management an...
Article
Behavioural syndrome, which refers to a suite of correlated behaviours across differing situations, has been identified in numerous animals, including fish. The presence and conservation of a behavioural syndrome throughout evolutionary times suggests it confers various advantages at a population level. In eels, such as the European eel (Anguilla a...
Article
Full-text available
The emergence of an animal’s personality is the result of interactions between genetics, environment and experience. It is known that individuals are able to modulate their behaviour according to the context or the social environment. Many studies have shown for example, that familiarity among conspecifics diminishes aggressiveness, although little...
Article
Full-text available
Abstract To address the impact of cadmium sulphide nanoparticles (CdSNPs) of two different sizes (8 and 50 nm), Danio rerio zebrafish were dietary exposed to very low doses: 100 or 40 ng CdSNPs/day/g body weight for 36 or 60 days, respectively. The results obtained using RAPD-PCR genotoxicity test showed genomic alteration since the number of hybri...
Article
Full-text available
The zebrafish, Danio rerio (Hamilton, 1822) has been widely used as a vertebrate model in scientific research and there are many advantages to its use in developmental and physiological studies, such as the transparency of the cho-rion, production of numerous eggs, a sequenced genome and no major rearing difficulties (Lawrence, 2007; Westerfield, 2...
Article
Full-text available
In European eel, it has been proposed that the undifferentiated gonad would develop into either an intersexual stage (Syrski organ) or directly into an ovary. The Syrski organ could then develop into either an ovary or a testis. In the present study, glass eels were raised until they reached a minimum size of 29 cm for histological sex assessment....
Article
Full-text available
Two cases of intersexuality are reported for the first time in European eel, Anguilla anguilla (at the beginning of the silver eel stage), within 140 fish caught as glass eels in the south-west of France and reared in tanks at 17°C. Cysts containing spermatozoa were observed in ovaries with pre-vitellogenic oocytes. This feature is very uncommon, e...
Article
Abstract – Social interactions impact growth rate of animals in different ways such as direct or indirect competition for food and/or territories. In this study, behaviour of glass eels and elvers was described throughout three trials of 9 days spread out over 3 months. The impact of recruitment season (spring and autumn runs) and glass eels’ prope...
Article
Full-text available
The impact of a daily ration of food containing gold nanoparticles (AuNPs) of two sizes (12 and 50 nm) was investigated in the zebrafish Danio rerio at very low doses (from 36-106 ng gold/fish/day). AuNP exposure resulted in various dysfunctions at the sub cellular scale, and AuNP concentration in food, AuNP size and exposure duration modulated the...
Article
Exposure to metal-contaminated water has been shown to result in a number of reproductive abnormalities in adult and larvae fish, such as failure of oocyte maturation and teratogenic effects. Recently, dietary uptake of metals by fish has been recognized as a critical route of exposure, however, the mechanisms of metal uptake and toxicity are poorl...

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Projects

Projects (8)
Project
Based in South Africa and built upon a South African-French cooperation, LIMAQUA develops an interdisciplinary research and training programme to tackle nutritional and sustainability challenges of marine aquaculture in the region. The objectives are to develop sustainable marine aquaculture practices for target species, an integrated approach to marine aquaculture, aquaculture-based food and nutritional products, provide capacity-building & training, and foster South-South collaborations within Africa.
Archived project
Study the possible link between cortisol and environmental sex determination in European Seabass
Project
To study the effects of global warming on the sexual fate and reproductive parameters of various fish species of aquaculture interest through molecular and physiological techniques to improve their management under farming conditions.